Heater Question

[Melbell]

I have been searching for a heater for my new betta for about a week. I looked in all the pet stores in my town and the smallest heater I could find was a 50 watt tetra. On the case it says it is for tanks sizes 2-5 gallons, but my tank is only 1.5 gallons. Would it be bad if I were to use this heater in my fish tank? I live in a really cold climate, so I'm worried about how warm Fluffy (my betta) is. Thank you for your help in advance.

[MrVampire181]

It's safe..I use them in my gallon jars.

[lilbloofish]

Just monitor the temp because you might need to set it at a lower temp.